The present invention relates to a high frequency transmitter-receiver, and more particularly to a high frequency transmitter-receiver employing an antenna-equipped system suitably used for vehicle-mounted radar equipment.
The high frequency transmitter-receiver used for a conventional vehicle-mounted radar equipment has a base plate, on which a circuit board is mounted, and an antenna substrate adhered astride an antenna base. It is because the base plate is advantageous to be smaller in terms of costs, while the antenna substrate is a flat antenna and desired to be large to obtain directivity of the radar.
The conventional high frequency transmitter-receiver has a base plate which is made of a metal having a low coefficient of linear expansion, such as a Kovar, to form a glass coaxial cable. Meanwhile, an antenna base 102 is made of iron, aluminum or the like. As a result, there is a disadvantage that a difference of the coefficient of linear expansion between the base plate and the antenna base is large, so that a thermal stress is produced in the antenna substrate at a position corresponding to the boundary part between the antenna base and the base plate, and an antenna pattern formed on the antenna substrate is distorted and broken.
It is an object of the present invention to provide a high frequency transmitter-receiver which can prevent an antenna pattern from being broken.
(1) In order to achieve the object of the invention, the present invention is directed to a high frequency transmitter/receiver which has a high frequency antenna comprised of an organic substrate and a metal pattern formed on the organic substrate and a base to which the high frequency antenna is fixed by adhering, wherein the base is formed of a plurality of bases and the high frequency antenna is fixed by adhering to cover the plurality of bases; and a gap between the plurality of bases to which the antenna is adhered satisfies the expression (an amount of change in gap size to a change in operating temperature)÷(an original gap size)xe2x89xa66%.
By configuring as described above, the antenna pattern can be prevented from being broken.
(2) In the above item (1), it is preferable that the metal pattern having an aspect ratio (width/thickness) of a width and a thickness of the metal pattern is 3 or more or a width of 100 xcexcm or more may be formed to cover the plurality of bases.
(3) In the above item (1), it is preferable that the metal pattern is formed on the side of the antenna within the boundary where the antenna is adhered to and to cover the plurality of bases.
(4) In the above item (1), it is preferable that a high frequency transmitter/receiver, which has a high frequency antenna comprised of an organic substrate and a metal pattern formed on the organic substrate and a base to which the high frequency antenna is fixed by adhering, comprising a high frequency circuit mounted on the base; an external circuit for supplying power to the high frequency circuit and processing a signal; a plurality of conducting pins which are supported by an insulator in an opening formed through the base and electrically connect the high frequency circuit with the antenna and the high frequency circuit with the external circuit; and a recess which is formed in the base to have the conducting pin located at back of the antenna surface with respect to a direction of transmitting and receiving a signal to and from the antenna and which is covered by the antenna.
By configuring as described above, effects of a power supply line and a signal processing line on the antenna can be reduced.
(5) In order to achieve the aforementioned object, the present invention is also directed to a high frequency transmitter/receiver, which has a high frequency antenna comprised of an organic substrate and a metal pattern formed on the organic substrate and a base to which the high frequency antenna is fixed by adhering, comprising an opening formed through the base; and a module which is mounted on one side of the base having the high frequency antenna mounted on the other side and which has a high frequency circuit for supplying a signal to the antenna made airtight; wherein the antenna is connected to a power supply line formed on the module through the opening.
By configuring as described above, the antenna pattern can be prevented from being broken.
(6) In the aforementioned item (5), it is preferable that the power supply line is a coaxial cable having an impedance of about 50xcexa9 and made of glass and a core; the opening forms a coaxial cable having an impedance of about 50xcexa9 by the core and air in the opening; and a circuit with a matching impedance is formed on the antenna or the high frequency circuit.
(7) In order to achieve the aforementioned object, the present invention is also directed to a high frequency transmitter/receiver, which has a high frequency antenna comprised of an organic substrate and a metal pattern formed on the organic substrate and a base to which the high frequency antenna is fixed by adhering, comprising an opening formed through the base; and a module which is mounted on one side of the base having the high frequency antenna mounted on the other side and which has a high frequency circuit for supplying a signal to the antenna made airtight; wherein the antenna has a power supply line formed on the module and the opening electromagnetically connected to form an impedance matching circuit on the antenna or the high frequency circuit.
By configuring as described above, the antenna pattern can be prevented from being broken.
(8) In the above item (7), it is preferable that the antenna is electromagnetically connected by a waveguide structure formed on the module to form an impedance matching circuit on the antenna or the high frequency circuit.
(9) In order to achieve the aforementioned object, the present invention is also directed to a high frequency transmitter/receiver which has a high frequency antenna comprised of an organic substrate and a metal pattern formed on the organic substrate and a base to which the high frequency antenna is fixed by adhering, wherein the base is a ceramic substrate and has a module which is mounted on one side of the base opposite of the side to which the high frequency antenna is mounted and which has a high frequency circuit for supplying a signal to the antenna; and the module is electrically connected to the antenna through the ceramic substrate by a coplanar line.
By configuring as described above, the antenna pattern can be prevented from being broken.
(10) In order to achieve the aforementioned object, the present invention is also directed to a high frequency transmitter/receiver, which has a high frequency antenna comprised of an organic substrate and a metal pattern formed on the organic substrate and a base to which the high frequency antenna is fixed by adhering, wherein the base is a ceramic substrate and has a module which is mounted on one side of the base opposite of the side to which the high frequency antenna is mounted and which has a high frequency circuit for supplying a signal to the antenna; and the module is electrically connected to the antenna through the ceramic substrate by a coplanar line, and the antenna substrate is adhered to the ceramics substrate without extending off the ceramics substrate.
By configuring as described above, the antenna pattern can be prevented from being broken.